We won a really nice piece of business a couple of weeks ago and this is how it happened. In the first instance our new client turned to his social search engine, sometimes called a business network. Once he'd narrowed down his search to us and a few others he ran some checks to see if our current clients would endorse our services, in other words he checked on who was 'linking' to us.
Their first pass was to ask a trusted resource for some recommendations. Their second was to check out our credibility. Sound familiar? It should because that's what search engines do! Confused?
A search engine rolls the two actions described above into one. First it finds relevant matches that meet the searches needs then it ranks them in order of credibility. Your job when optimising your site is to create relevant content and raise your site's credibility by securing relevant links.
Hope this helps.